FIRST EVIDENCE OF THE OCCURRENCE OF THE CAJAL BODY-LIKE STRUCTURES IN BIVALVE OOCYTES

Abstract

Discovered by Santiago Ramón y Cajal in 1903, Cajal bodies are the most studied nuclear bodies. To date, they have been reported from many eukaryotic organisms such as insects, fish, frogs, birds, mammals, plants and yeast. In this study, Cajal body-like structures were observed in the germinal vesicle of the developing oocytes of Donax trunculus by electron microscopy, which have not been seen or reported in the oocytes of any of the bivalves investigated to date. Cajal bodies, the number and size of which vary depending on cell type and species, are 0.1-1 μm in diameter and 2-10 in somatic cells, while oocyte Cajal bodies are 50-100 in each nucleus and their diameter can range between 1 and 30 μm. In this study, the number and size of Cajal body-like structures in the oocytes of Donax trunculus was found to be 6-12 and 0.8-1.2 μm, respectively. In this respect, Cajal bodylike structures of Donax trunculus resemble Cajal bodies in somatic cells. Donax trunculus may be a good model organism for cell biologists and molecular biologists who study the structure and function of Cajal bodies.